Drilling rig



1957 G. H. WILDERMAN DRILLING RIG 3 Sheets-Sheet 1 Filed Oct. 21, 1964 V- 1967 G. H. WILDERMAN 3,351,142

DRILLING RIG 3 Sheets-Sheet 2 Filed Oct. 21, 1964 N 1967 G. H. WILDERMAN 3,351,142

DRILLING RIG Filed Oct. 21, 1964 3 Sheets-Sheet :5

United States Patent o 2 Claims. 61. 173-147 This invention relates to a new and improved apparatus for drilling shallow bore holes (20 feet to 250 feet in depth), and more particularly to an apparatus for drilling bore holes adapted to receive an explosive charge.

In geophysical exploration, a relatively large number of blast holes are required and these vary in depth from say fifty to about two hundred feet. Drilling conditions and penetration rate will of course vary depending on the resistance of the material through which the hole is being drilled. Since this resistance will vary widely, it is usually necessary to employ heavy drilling equipment to ensure all types of holes will be easily drilled, but this poses a transportation problem if inaccessible areas are to be tested. Consequently, geophysical exploration, because of equipment size and weight, becomes quite expensive in remote areas.

The actual drilling of blast holes is usually carried out by mounting the drilling rig at the end of a base such as a truck or platform and applying additional downward pressure to the drill bit through the rig by elevating the opposite end of the base by means of pull down cables, pull down drains or hydraulic cylinders. However, only a limited amount, about 25%, of such total available pressure can be applied to the drilling rig because the whole assembly becomes a simple lever, with the fulcrum close to, or at the other end of the machine. Therefore, drilling operations must require heavy equipment to meet the varied resistances of formations encountered when drilling.

The present invention provides a lightweight drilling rig which is portable by means of a helicopter, and which is designed such that a major portion of the weight of the drilling rig is available to produce a downward thrust on the drill which forms a part of the complete rig. A major feature of the present invention resides in the positioning of the drilling axis and drilling rod with respect to the drilling rig such that the drilling axis corresponds substantially to the line of action of the force of gravity acting on the complete drilling rig. The complete drilling rig may therefore be made considerably lighter than devices in the prior art, while at the same time being capable of exerting sufiicient pull down pressure through cables on the drill rod to operate even under very difficult drilling conditions.

It is therefore an object of this invention to provide a drilling rig sufficiently light for helicopter transportation and capable of utilising about 75% or more of the drilling rig weight to provide pressure on the drill bit when drilling.

Other objects of the invention will become apparent from the description to follow.

In the diagrams:

FIG. 1 represents a perspective view of a folded drilling rig being lowered from a helicopter on to a base;

FIG. 2 represents a perspective view of the rig after it has been mounted on the base; and

FIG. 3 represents a perspective view of the rig after erection on the base and in position for drilling.

The rig components are conventional and comprise a rotatable mast 1, support columns 2 for the mast, and bearings 3, 3 about which the mast may be rotated from 3,351,142 Patented Nov. 7, 1957 an erect position for drilling purposes to a folded position for transportation. The rotation is accomplished by hydraulic cylinder 19 and piston 19a. The entire assembly including reducing gears, drive rods, etc., are mounted on a base 4a, the mast being at one end of the base. At the other end of the drill base 4a is a support on which the mast rests when folded. This support comprises two vertical posts, 6, 6 and a horizontal support bar 7, with diagonal reinforcing crosspieces 8, 8. The rig may be lowered by a helicopter as shown in FIGURE 1 onto a power base 4. Power base 4 comprises a rigid framework of steel. Motor 14 is mounted near one end of power base 4 and operates the drill rod 9 as well as the other components of the drilling assembly.

The drill base 4a and the power base 4 are then clamped together, the mud or air lines are joined, and the drive shaft 17 is connected to the gear box 20 thereby to supply power to drill rod 9 and its draw down mechanism; hence the two assemblies effectively become unitary and are collectively referred to as the base of the drilling apparatus.

In accordance with the present invention the several components of the drilling apparatus are arranged on the base such that mast 1, drill rod 9 and turntable 10 are positioned at approximately the centre of gravity of the complete drilling apparatus. It therefore follows that the drilling axis will be substantially in correspondence with the line of action of the force of gravity exerted on the drilling apparatus. Turntable 10 is provided with a square hole 11 for engagement with the drilling rod which may be raised or lowered by pulleys 12. The motor 14 and its drive system is mounted on power base 4 and operates the drill rod 9, the hydraulic system, and the various cable and pulley systems incorporated in the drilling apparatus. Motor 14 drives these various components through drive shaft 15 which, in turn, drives shaft 17 and thru the belt drives 16, 16. As an alternative, the drive shaft 17 may be omitted and the drill base 4a provided with its own power unit, separate and in addition to the power unit on the power base 4. The power base 4 is provided with jacks 18 which may be utilized to level the complete drilling unit.

Cables 13, 13 are connected at their one end to the upper ends of the drill rod 9 and at their other ends to a suitable winch drum arrangement which supplied the necessary draw down pressure to drill rod 9 via the cables 13, 13. By virtue of the fact that the drilling axis passes either through or is quite near to the center of gravity of the system, and corresponds closely to the line of action of the force of gravity exerted on the drilling axis, a maximum force equal in magnitude to at least of the combined weight of the drilling assembly may be exerted on the drill rod 9.

The present arrangement is capable of applying much greater pressure to a drilling rod than other systems having the same weight and therefore the rig may be lightened while still retaining an equivalent pressure producing capability. As a result, this lightened rig may be transported with present helicopter facilities into and base within said drilling axis, draw down means suitably mounted on said drill base and attached to said rotary table and said drilling mast, power means and pressure blower means on said power base, power take oil means from said power means for said pressure blower means, gear box means on said drill base, hoisting means on said drill base, power take oil means for said draw down means, power take off means for said transmission turntable, power take off means for said hoisting means, flexible coupling means connecting said rotary table and said pressure blower means, said drill base positioned on said power base such that said drilling axis corresponds to and is substantially parallel to the center of gravity of said drilling apparatus such that at least 75% of the weight of said drilling apparatus is available to produce downward thrust, said drill base and said power base adapted to be transported readily by helicopter.

2. A portable rotary drilling apparatus comprising a drill base, a power base, said drill base comprising frame means for detachably mounting said drill base on said power base, a drilling mast pivotally mounted on said drill base and adapted to swing from a working vertical position to an inclined position on said drill base, a drill rod slidably mounted within said drill mast, a vertically positioned transmission turntable mounted on said drill base, draw down means mounted on said drill base andoperatively attached to said drilling rod and apparatus is available to produce downward thrust, said power base comprising power means operatively connected to said drill base to operate said drilling apparatus, said drill base and said power base adapted to be transported readily by helicopter.

References Cited UNITED STATES PATENTS 2,075,185 3/1937 Eiler 173147 2,838,282 6/1958 Colquitt l73l47 2,869,826 1/1959 Thornburg 173147 3,012,619 12/1961 Farque 173-147 3,047,080 7/1962 Gunther 17328 FRED C. MATTERN, 111., Primary Examiner.

L. P. KESSLER, Assistant Examiner. 

2. A PORTABLE ROTARY DRILLING APPARATUS COMPRISING A DRILL BASE, A POWER BASE, SAID DRILL BASE COMPRISING FRAME MEANS FOR DETACHABLY MOUNTING SAID DRILL BASE ON SAID POWER BASE, A DRILLING MAST PIVOTALLY MOUNTED ON SAID DRILL BASE AND ADAPTED TO SWING FROM A WORKING VERTICAL POSITION TO AN INCLINED POSITION ON SAID DRILL BASE, A DRILL ROD SLIDABLY MOUNTED WITHIN SAID DRILL MAST, A VERTICALLY POSITIONED TRANSMISSION TURNTABLE MOUNTED ON SAID DRILL BASE, DRAW DOWN MEANS MOUNTED ON SAID DRILL BASE AND OPERATIVELY ATTACHED TO SAID DRILLING ROD AND SAID DRILLING MAST, SAID DRILLING MAST, DRILL ROD AND TRANSMISSION TURNTABLE BEING SO POSITIONED THAT THE DRILLING AXIS DEFINED THEREBY CORRESPONDS TO AND IS SUBSTANTIALLY PARALLEL TO THE CENTER OF GRAVITY OF SAID DRILLING APPARATUS SUCH THAT A MAJOR PORTION OF THE WEIGHT OF THE DRILLING APPARATUS IS 